Exception Vectors
Interrupt Controller 9-3
programmable, but the lower 3 bits reflect the interrupt level that is being serviced. All interrupts are
maskable. Writing a 1 to a bit in the interrupt mask register disables that interrupt. If an interrupt is
masked, you can find out its status in the interrupt pending register.
9.2 Exception Vectors
A vector number is an 8-bit number that can be multiplied by four to obtain the address of an exception
vector. An exception vector is the memory location from which the processor fetches the address of a
software routine that is used to handle an exception. Each exception has a vector number and an exception
vector, as described in Table9-1. User interrupts are part of the exception processing on the MC68VZ328,
and the vector numbers for user interrupts are configurable. For addit ional i nformation regardin g excepti on
processing, see the M68000 Family Programmer’s Reference Manual.
Table 9-1. Exception Vector Assignment
Vector Number Address Number
Space1Assignment
Hex Decimal Decimal Hex
000000SP Reset: initial SSP2
1 1 4 004 SP Reset: initial PC
2 2 8 008 SD Bus error
3 3 12 00C SD Address error
4 4 16 010 SD Illegal instruction
5 5 20 014 SD Divide-by-zero
6 6 24 018 SD CHK instruction
7 7 28 01C SD TRAPV instruction
8 8 32 020 SD Privilege violation
9 9 36 024 SD Trace
A 10 40 028 SD Line 1010 emulator
B 11 44 02C SD Line 1111 emulator
C1248030SD Unassigned, reserved3
D1352034SD Unassigned, reserved3
E1456038SD Unassigned, reserved3
F 15 60 03C SD Uninitialized in terrupt vector
10–17 16–23 64–92 040–05C SD Unassigned, reserved3
18 24 96 060 SD Spurious interrupt4
19 25 100 064 SD Level 1 interrupt autovector